420 



THE EVOLUTION OF MAN. 



naculum testis) (Fig. 328, M, gh) ; in the female, the round 

 uterus-cord (Fig. 328, F,r). In the latter the ovaries 

 migrate more or less in the direction of the small pelvis, or 



Fig. 328, M. 



Fig. 328, F. 



Fig. 328. — Original position of the sexual glands in the abdominal cavity 

 of the human embryo (of three months). Fig. 328, M, male (natural size) : 

 h, testis; gh, the conduoting-cord of the testis; wg, seed-duct; h, urinary 

 bladder ; uh, lower hollow vein (tiema cava) ; nn, supplementary kidneys ; 

 n, kidneys. Fig. 328 F, female (somewhat enlarged) : r, round uterus-oord 

 (below this the urine-bladder, above it the ovary) ; r', kidney ; s, sup- 

 plementary kidney ; c, blind-intestine (caicum) ; o, small net ; om, large 

 net ■ (between the two is the stomach) ; I, spleen. (After KoUiker.) 



even enter this. In the male the testis quits the abdominal 

 cavity altogether, passing' through the groin-canal, and 

 enters a sac-shaped, distended fold of the external skin- 

 covering. The coalescence of the right and left folds 

 (" sexual folds ") gives rise to the testis-sac (scrotuin). The 

 various Mammals exhibit the various stages of this migra- 

 tion. In the Elephant and in Whales the testes descend 

 very little, and lie below the kidneys. In many Gnawing 

 Animals (Rodentia) and Beasts of Prey (Carnaria) they 

 enter the groin-canal. In most higher Mammals they pass 

 down through this into the testis-sac ; usually the walls of 



